This invention concerns containers for transporting animals, especially laboratory animals.
Smaller laboratory animals such as mice, rats, rabbits, hamsters, gerbils, and the like are generally shipped from a supplier to a laboratory in shipping crates formed of cardboard and lined with wire mesh. For example, Charles River Laboratories regularly uses crates constructed of die cut corrugated cardboard and metal screen materials and secured by metal staples. The constructed crates include six side-positioned vent areas covered with an air-filtration material which is permeable to air and minimizes passage of airborne contaminates into the crates. The crates are designed with slant-in sidewalls to enable air passage between crates that are stacked on pallets during transport.
Typical crates are sized about 24.5 inches in length, 16.5 inches in width, and 5.5 inches in height for transport of up to about thirty mice or up to about eight rats. A higher crate--about 10 inches in height--is typically used for the transport of up to two guinea pigs. In general, crates are sized to maximize transport efficiency on pallets.
The crates are also designed to properly support animal health during the shipping period. While shipping periods are variable, proper design generally assumes a period of at least 72 hours, even though most deliveries will be completed within a 48-hour period.
As noted above the crates are typically corrugated cardboard. An interior lining or coating is generally provided to make the crate impervious to animal wastes. A further interior lining is generally provided to prevent the animals from gnawing or chewing through the container.
The crates are constructed from two exterior parts: a base and a lid. The lid will usually be partially attached to the base before introducing animals for shipment. After the animals are loaded the remainder of the lid is attached to the base. When unloading the animals after shipment, the process is reversed.
A principal difficulty with the crates currently in use is that they are difficult to open. One method for attaching the lid of the container to the base is stapling. However, not only is the stapled container difficult to open, the staples protruding around the edges of the opened container are hazardous to both the animal and its handler. Another method is to add a perforated tear-strip along the top, front edge of the crate. However, the strip often does not function properly or easily and, to complete opening from the end to the mid-crate area, the two side edges of the lid must be lifted against the strength of the stapled corrugated materials, resulting in torn corrugated and uneven tear lines.